The co-occurrence of language impairments and attention deficits in children receiving therapeutic services has been well-documented, but the nature of this comorbidity is poorly understood. Between-group designs have been the primary basis for this association, where the performance of a target group of affected children was compared to a control group of typically developing children; however, recent findings of symptom specificity for both specific language impairment (SLI) and Attention Deficit/Hyperactivity Disorder (ADHD) suggest that direct comparisons between the psycholinguistic and socioemotional characteristics associated with these two highly prevalent disorders are timely and urgently needed. Funds are requested to support the first phase of a research initiative directed at clarifying the relationship between attention deficits and language impairment. Under consideration is the hypothesis that there are distinctive psycholinguistic and socioemotional profiles associated with SLI and ADHD (c.f. Redmond & Rice, 1998; 2002; Rice, 2003; Tannock & Schachar, 1996). In the proposed project, the feasibility of differentiating SLI from ADHD will be established using narrowly defined clinical groups. Sixty 7-8 year old children, representing 20 children with SLI, 20 children with ADHD and 20 children with typical development (TD) will participate. Three specific aims will be addressed: Aim 1: To compare the psycholinguistic proficiency of children with SLI, children with ADHD, and children with TD. Aim 2: To compare executive functioning in children with SLI, children with ADHD and children with TD. Aim 3: To compare the socioemotional profiles of children with SLI, children with ADHD, and children with TD. Children's psycholinguistic proficiency will be evaluated using established protocols for tense marking, non-word repetition, sentence recall, and narrative production. Children's executive functioning will be evaluated using a non-verbal continuous performance task. Behavioral rating scales and self-report measures will be used to assess children's socioemotional status. Direct comparisons of SLI and ADHD symptomotology will sharpen our understanding of the phenotypic boundaries associated with each disorder. Given the academic and social risks associated with misdiagnosis and the poor prognosis associated with untreated comorbidity, this research impacts upon several key public health concerns. [unreadable] [unreadable] [unreadable]